43 



Stat. 95. 5°43'.5\., ii9°4o' E. 22 spec. 



Stat. 102. 6° 4'.iN., I20°44' E. 17 spec. 



Stat. 105. 6° 8' N., 121° 19' E. 6 spec. 



Stat. 137. o°23'.8N., 127° 29' E. 3 spec. 



Stat. 139. 0° 1 r S., 1 27° 25' E. 2 spec. 



Stat. 151. o°i2'.6S., 1 29° 48' E. 5 spec. 



Stat. 178. 2° 40' S., I28°37'.5E. 4 spec. 



Stat. 211. 5°4o'.7 S., i20°45'.5 ^- ' spec. 



The species is very abundantly distributed over the whole region. 



No other species exhibits .so many variations. \"ery striking is the difference in size 

 among the specimens themselves. The lateral points of the small-sized individuals are generally less 

 developed, the dorsal lip is not prolonged into a rostrum, and the shell is hyaline. In the larger 

 specimens, however, the lateral points are more conspicuous, while the rostrum is long, and 

 the shell coloured whitish. These characters are not absolutely connected with the size, and the 

 opinion, according to which the small specimens represent young stages, is erroneous, as Boas ^) 

 pointed out. They are adult individuals, like the large ones, which will not grow further. 



Hyalaca angulata Souleyet was found at nearly every station from which Cavolinia 

 loncirostris has been recorded. But the transitions to this form are so numerous too, that it 

 is impossible to regard the species of Souleyet as a distinct one. 



Boas ") described a variety, in which the lateral points are more or less curved upwards. 

 Some specimens of the collection, gathered by the Siboga, agree with his description (Stat. 102), 

 but here, too, gradual transitions make it almost impossible to maintain the distinctness of 

 this variety. 



I may remark further that a small brown spot sometimes occurs on the dorsal side of 

 the shell, just above the closing apparatus, while the strong dorsal median rib also exhibits a 

 brownish colour of more or less extension. These characters, not in any way connected with 

 any other constant peculiarity of the shell, do not allow me to make a new variety. 



8. Cavolinia inflexa (Lesueur). 



1S13. Hyalaea inflexa Lesueur, Memoire sur quelques animau.x Mollusques, etc., Nouv. Bullet. 



Soc. Philom., vol. Ill, p. 2S5, pi. V, fig. a,,A,B,C,D. 

 182 1. Hyalaea elongata Lesueur in: DE Blainville, Diet. d. Sc. Nat., vol. XXII, p. 82. 



1835. Hyalaea vaginellina Cantraine, Bullet. Acad. d. Sc, Bruxelles, vol. II, p. 380. 



1836. Hyalaea labiata d"Orbigny, Voyage dans TAmerique meridionale, vol. V, p. 104, 



pi. VI, figs. 21 — 25. 

 1836. Hyalaea uncinata Honinghaus in: Phiuppi, Enum. Moll, utriusque Siciliae, vol. I, 



p. 101, pi. VI, fig. 18. 

 1 84 1. Hyalaea vaginella Cantraine, Malac. medit., p. 28, pi. I, figs. 6 — 6a. 

 1850. Cavolma inflexa Gray, Catalogue of the Mollusca in the collection of the British 



Museum, prt. II, Pteropoda, p. 9. 

 1877. Hyalaea (Diacria) inflexa Sowerby, in: Reeve, Conch. Icon., vol. XX, Pteropoda, 



pi. Ill, figs, ija — ijb. 

 1877. Hyalaea (Diacria) labiata Sowerby, Ibid., figs. \%a — 18;^. 



1) Spolia atlantica, p. 102. 



2) L. c. s. 103. 



