68 H. HEATH aud M. H. SPAULDING, 



Gleha but Cymhuliopsis and since Corolla is the older name the latter 

 becomes a synonym. 



In looking over the original description and at a drawing kindly 

 sent by Mr. Dall it became at once evident that our species was 

 almost identical with Corolla speciabilis. There were some differences 

 in color but otherwise the resemblance was so close as to leave little 

 doubt that our name should be considered a synonym of Corolla 

 speciabilis Dall. This fact in nowise effects our work on the ana- 

 tomy of the species which is herewith described. 



The general form of the individuals of this species is shown in 

 Figs. 1 and 2 while Fig. 7 shows accurately the position of the more 

 important organs. The symmetrical proboscis, corresponding to the 

 head region of other gastropod molluscs, is comparatively thin and 

 broad, and is free from the fin for nearly half of its length. Its free 

 margins are developed into a groove composed of high columnar cells 

 richly ciliated and innervated by a profuse nerve supply from the 

 cerebral ganglia. It thus appears to function as an organ of special 

 sense and as a contrivance for collecting and driving the food par- 

 ticles into the mouth situated on the anterior border of the proboscis 

 in the median plane. In every one of forty six specimens carefully 

 examined there were two tentacles symmetrically disposed on each 

 side of the mid line. In preserved individuals they are usually little 

 more than knob-like protuberances but in two or three specimens they 

 were upwards of a millimetre in length. Judging from their abundant 

 nerve supply they are scarcely to be considered rudimentary organs 

 and special retractor muscles are probably responsible for their con- 

 tracted condition in a preserved state. 



The mouth, funnel-shaped in form, and possessing two ciliated 

 grooves along its lateral borders, passes into the oesophagus which 

 is invariably symmetrical in form and position. The last named 

 structure, somewhat conical in shape as the figures indicate, extends 

 directly from the mouth to the visceral mass or nucleus. This part 

 of the body, also symmetrically disposed in the mantle cavity some- 

 what behind the centre of the casque, consists of the stomach, in- 

 testine, liver and the reproductive organs and on its dorsal surface 

 affords attachment for the heart and kidney. 



The foot or fin, modified into a swimming organ, differs widely 

 in form from the usual type of gastropod foot. It is operated by 

 two systems of muscle bands, one set close to the ventral and the 

 other to the dorsal surface of the fin. Each system consists of three 



