ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 317 



Azores at a depth of 1557 metres. Numerous specimens were found 

 attached to a fragment of a Cephalopod beak. The new form is described 

 as Bathysciadium conicum g. et sp. n., aud some account of its structure 

 is given by Prof. Paul Pelseneer. It has a simple conical shell, is with- 

 out gills or ctenidia, has one auricle, a nervous system like that of the 

 Patellidas, two remarkable otocysts, each containing a single spherical 

 otolith, and a long radula with ten teeth in a row. There are two 

 nephridia, the left being larger than is usual in the Patellidae. The 

 animals are hermaphrodite, and there is a long copulatory organ. As 

 to the systematic position, the animal has the general characters of the 

 limpets, but differs sufficiently from the members of the existing families 

 to merit the erection of a new family for its reception. 



Two New Neomenians.* — Dr. G-. Pruvot describes Stylomenia sal- 

 vatori g. et sp. n., which exhibits in its main features transitional 

 characters of much interest. Like the genus Ismenia, it must be referred 

 to a primitive group, connected on the one hand with the tribe of Pro- 

 neomenidse, and on the other hand with the Neomenidse. A second form 

 is Strophomenia lacazei g. et sp. n., which is probably derived from 

 Bhopalomenia aglaoplienise or some adjacent form. It most closely re- 

 sembles Pruvotia sopita, and perhaps an Australian Notomenia described 

 by Thiele. It represents, in any case, one of the most modified Neo- 

 menians, degenerate under the influence of parasitism. 



5. Lamellibrancbiata. 



Locomotion in Solenomya and its Relatives.! — Dr. G. A. Drew 

 notes that the movements of burrowing and the muscular systems are 

 quite similar in all the three genera Nucula, Yoldia, and Solenomya. 

 He takes Yoldia as an example. The movements of burrowing consist 

 of thrusting the closed foot far out of the shell anteriorly, spreading 

 the flaps, and withdrawing it with the flaps spread. The spread flaps 

 are closed together when they come to the margin of the shell, and the 

 foot is ready for another thrust. Jf these movements take place in mud; 

 they will cause the animal to change its position. The closed foot is 

 wedge-shaped, and easily penetrates the mud, while the spread flaps form 

 a very perfect anchor. Anchored in this way, when the retractor muscles 

 of the foot contract, the shell is pulled to the position of the flaps. As 

 repeated thrusts and retractions follow each other with great rapidity, 

 the animal can bury itself very promptly — seven or eight inches in a 

 very few seconds. What special enemies they have has not been deter- 

 mined, but it seems that flounders and cormorants feed upon them. With 

 regard to these enemies this method of escape must be very effective. 



Another combination of movements common with Yoldia, and fre- 

 quently performed by Solenomya, are the movements of leaping, probably 

 of importance when the animal finds itself stranded on some hard smooth 

 surface where the movements of burrowing are not effective. The foot 

 is bent back under the valve on which the specimen is lying, the flaps 

 spread, the shell turned nearly on its dorsal border, and the expanded 

 disk planted on the bottom. The posterior foot-muscles then contract 

 with a sudden jerk. If the foot remains firm on the disc, this results in 



* Arch. Zool. Expe'r., vii. (1899) pp. 4(51-509 (3 pis.). 

 t Auat. Anzeig., xvii. (1900) pp. 257-66 (12 figs.). 



