116 NACELLA. 



3708. Nacella mytiloides SCHUM., Syst. Vers Test. p. 179. N. 

 cymbularia LAM., An. s. Vert, vi, p. 335. PHIL., Abbild., iii, t. 1, 

 f. 2 (not P. cymbularia DELESSERT, Rec. de Coq. t. 23, f. 8, P. 

 cenea Martyn). P. cymbuloides LESSON, Voy. de la Coquille, p. 

 422. Nacella cymbalaria (sic) ROCHEBRUNE & MABILLE, Mission 

 Cape Horn p. 97. Nacella eompressa MABILLE & ROCHEBRUNE, /. 

 c. p. 98, t. 5, f. 9. P. cymbium PHIL., Arch. f. Naturg. 1845, p. 60 ; 

 Abbild. p. 7. P. vitrea PHIL., Abbild., t. 1, f. 4. Nacella vitrea 

 THIELE, Das Gebiss, ii, t. 28, f. 28 (dentition). P. hyattna PHIL., 

 1. c., f. 3. Nacella hyalina THIELE, I. c., f. 29 (dentition). Nacella 

 mytilina BALL, Am. Journ. Conch, vi, p. 274, t. 16, f. 26 (dentition). 

 THIELE, I. c., t. 28, f. 30, (dentition). P. (Nacella) mytilina SMITH, 

 Philos. Trans, clxviii, p. 181. 



The thin texture, oblong form and anterior apex are diagnostic 

 of this delicate species. It varies considerable in the position of the 

 apex ; in some specimens it is nearly marginal. The color is also 

 variable, " some being of a general grayish tint, varied at intervals 

 with darker concentric rings and often a few radiating palish stripes 

 on the ribs. Others are uniformly yellowi'sh-brown, others pale luteous 

 broadly striped with black, and finally, others are of a uniform 

 pale horny color, but all have the apex cupreous." ($.) 



There is.no reason for ignoring Helbling's work on this species 

 except that his book is not a common one. But surely if Martyn's 

 names are to be accepted, one cannot close the door upon the 

 properly proposed names of the German author. 



The synonymous P. eompressa Mab. & Rochebr. is figured on pi. 

 50, fig. 37. 



Var. HYALINA Phil. PI. 50, figs. 38, 39. 



Apex at or very near the anterior margin. The specimens before 

 me show numerous forms between this and the typical mytilina. 



A large series of radulse must be examined before the differences 

 found by Thiele can be acknowledged to be of specific value. This 

 organ no doubt varies just as the shells do, in minor characters. In- 

 deed there is often considerable variation in the teeth of a single 

 odontophore ! 



Section Patinella Dall, 1871. 



Patinella DALL, Amer. Journ. Conch, vi, p. 272. THIELE, Das 

 Gebiss der Schuecken, ii, p. 330, 1891. 



