1901.] NATURAL SCIENCES OF PHILADELPHIA. 509 



CYMBTJLIOPSIS VITREA, A NEW SPECIES OF PTEROPOD. 

 BY HAROLD HEATH AND M, H. SPAULDING. 



Ou tlie 27th of Deceral)er, 1900, a large number of iudividuals 

 of the species about to be described were taken at or near the sur- 

 face of Monterey Bay, California, and twice since that lime great 

 shoals have been noted in the same locality. With the use of 

 formalin, formalin-alcohol and picro-formalin their natural appear- 

 ance and structure have been ^ireserved with exquisite fidelity, and 

 will be more fully discussed in a later paper. 



This species falls naturally into the genus Cymbiiliopsis proposed 

 by Pelseneer^ which was made to embrace the two species C. ovata 

 and C. calcola, but differs from these in several important respects. 

 The " shell " or casque (Peck),^ slightly asymmetrical, possesses 

 the characteristic slipper form and bears on its external surface 

 numerous small rounded tubercles which become smaller and more 

 closely grouped together near the posterior-dorsal surface. Its 

 aperture is large, unarmed and much wider than in C. ovata, but 

 is almost identical with that of C. calceola, and as in the latter, 

 its large cavity extends to the dorsal extremity. The maximum 

 length of the casque is 4 cm., with a width of 2.5 cm. 



The broad, perfectly symmetrical flattened proboscis constituting 

 the head region is in contact with the upper surface of fin, yet 

 free from it to a point immediately in front of the central nervous 

 system. Its edges are grooved and lead into the wide funnel- 

 shaped mouth and oesophagus. Dorsal to the latter and symmet- 

 rically placed are the tentacles having the form of small knob-like 

 projections, each of which is supplied with a strong nerve from the 

 cerebral ganglia. Peck noted the occasional absence of these 



^ Report ou the Pteropoda collected by H. M. S. Challenger during the 

 years 1873-1876, Part LXV, p. 96. Vide also The Nautilus, III, p. 30, 

 1889, where Dall shows CymhuUopsis to be identical with his earlier genus 

 Corolla. 



^ Peck, J. I., "On the Anatomy and Histology of Cymbuliop^is calceola," 

 Studies from the Biological Laboratory, Johns Hopkins University, Vol. 

 IV, No. '6. 



