ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 353 



matter was carefully estimated. The Zostera is relatively far richer in 

 pentosan compounds than the plankton organisms. The organic matter 

 of the sea-bottom was found to occupy an intermediate position between 

 the Zostera and the plankton with regard to the amount of pentosan 

 contained. 



The amount of nitrogenous matter digestible with pancreatin was 

 comparatively small, but the investigations of Biedermann and Moritz 

 point to the conclusion that bivalves are capable of digesting pentosan 

 which is present on the sea-bottom in considerable quantities. 



Iodine in Marine Animals.*— A. T. Cameron has enquired into the 

 iodine-content of marine animals in the neighbourhood of Nanaimo, 

 Vancouver Island. It is generally distributed, and seems to occur, as 

 Gautier showed, in organic combinations in the surface-water, in 

 inorganic form in the deeper water. Perhaps the Alga? may, in part. 

 utilize the organic combinations containing iodine. 



All the animals examined, except the free-floating forms and the 

 starfish' (Pyfatapodia), showed the presence of iodine in detectable 

 amount. It was very scanty in sea-cucumber and barnacle. In fishes 

 the thyroid is the only organ containing an appreciable amount. In 

 Squalus sucMii it was detected in the excretory organs. 



Iodine was found in marked quantity in the horny tube secreted by 

 the worm Diopatra.m the cellulose ("tunicine") test of the Tunicate 

 Pyura, and in the external cuticle of the horse-clam Schizotharus. In 

 sponges the iodine is contained in the spongin, a sclero-protein ; in 

 Gorgonids in the gorgonin, also a sclero-protein ; in the Serpulid tube 

 in conchiolin, also a sclero-protein. In the case of the bivalve Schizo- 

 thmrus, the cuticle is probably for the most part a keratin. 



Penis-bone in Squirrels.t — Oldfield Thomas finds that the struc- 

 ture of this bone, for which the term " baculum " is suggested, is of 

 service in classifying squirrels. In the common squirrel it is like a 

 spatula, or still more like a half-closed human right-hand, the shaft 

 forming the forearm, the blade of the spatula the hollowed palm, and 

 a small pointed projection on the right side corresponding to an out- 

 stretched thumb. Of this type are the bacula of the other Palawan bi< 

 species. But all the Indian and Malayan species hitherto referred to 

 Sciurus have bacula which are totally different from that of trui 

 Sciurus, and may be called compound. In all these there are two 

 parts: a shaft, or capulus, of varying length, and a separate blade, or 

 lamina, attached to the shaft by ligament, and slightly movable upon it. 

 There are two types of compound bacula. respectively more and less 

 specialized. The author shows how the characters of the baculum i 

 be utilized in classification. 



Retractor Penis in some LemuridaB.J — Ed. Rettererand 11. Neuville 

 report the presence of a retractor muscle of the penis in some Lemuri 



* Contributions Canadian Biol., 47th Rep. Dept. Fisheries, Ottawi pp 



51-88. t Ann. Nat. Hist., xv. (1915) pp. 383-7. 



X C.R. Soc. Biol. Paris, lxxviii. (1915) pp. 79-80. 



