Notes on the Natural History of Some Marine Animals (1938)

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Although sponges have but few enemies, they are subject to the predacious act'vities of certain other animals, especially gastropods, of which the nudibranchs are the most important. Lamellaria stearnsii Dall, a yellowish gastropod with an internal shell, seems to feed almost exclusively upon sponges, mainly the yellow sponge Lissodendoryx noxiosa de Laubenfels. I have also seen the cushion star, Patiria miniata (Brandt), making a meal of this incrusting sponge. Sponges usually remain fixed after the larvae become attached, but on the mud flats of estuaries of Southern California there is a sponge, Tetilla mutabilis de Laubenfels, which, when settl:ng, fastens itself in the mud by a strong, slender stalk (P1. 1, Fig. 2). This stalk, which is about two inches long, consists of a number of fine strands which are fringed at their lower ends so that they anchor the animal firmly. The sponge, which possesses but a single osculum when young, continues to grow until it reaches the size of a pigeon's egg or a little larger, whereupon it usually breaks loose from the stalk and is rolled about over the mud flats by the tides (P1. 1, Fig. 3). It may move a considerable distance from the place where it settled, continuing to grow until it becomes an irregular mass, six inches or more in diameter, having several oscula. I have never observed this sponge burrowing by contraction as some other sponges do. On April 25, 1935, I found thousands of young Tetilla, ranging from one fourth inch to two inches in length, anchored in the mud near Harbor Island in Newport Bay. Also, :t is usually considered that sponges are not readily grown in the laboratory, but at the Kerckhoff Marine Laboratory larvae of Sycon coronatum (?) (Ellis and Solander) (P1. 1, Fig. 1) often come in with the circulating water and become fixed in great numbers over the sides of the aquaria or upon solid objects in the aquaria, where, unless removed, they continue to develop unt I they reach a length of about three centimeters.