72 
proximal portion to the right issues the intestine, which bends 
directly down and passes slightly curving through heart to anus. 
On the under sides of the foot retractors a pair of small pa- 
pillae are visible; here the genital duets open. The sexes are se¬ 
parated and the gonads oceupy the posterior part of the body hump. 
In female individuals very large eggs are seen in follicles which 
are formed as in Pseudokellya (cf. Pelseneer 1903). 
The nephridia are comparatively small; they have long peri- 
cardial tubes and long communication; for the remaining part their 
outer sacs have smooth walls, and open opposite the genital pores, 
in the corner between foot retractors and visceral hump. 
Fam. Crassatellidae. 
Crassatella aurora Adams&Angas. 
(PI. II, figs. 40, 41). 
North Island: 2, 1 valve, I. 21.5, h. 16.2. — 10, 3 sps., 1. 15, 
h. 11.6, another sp.: 1. 16, h. 12.5. -- 11b, 1 sp., 1. 18.3. This 
species was until now known only from the Australian continent 
(Lamy 1917). I give a description and figures of the New Zea¬ 
land form in order to fix its characters for a comparison with the 
closely allied species (or varieties) C. carnea, banksi and bellula. 
Shell elongate ovate-trigonal, anterior end a little shorter, 
rounded, posterior end rounded subtruncate, dorsal margins straight, 
beaks sharply pointed. Lunula and escuteheon distinet, narrow and 
of equal length. Colour pale fawn with 2 broken rays of brown 
diverging from the umbonal region to the under margin dividing 
the surface into 3 subequal areas. Sculpture: strong, concentric, 
rounded ribs over the whole shell coincident with the growth lines 
in the middle, more or less defiected at a diagonal line behind 
the posterior colour ray, and then running obliquely to the growth 
lines, which are somewhat raised in the hind part of the valve; 
concentric sculpture evanescent close at the dorsal margins. Interior 
light rosy, brighter towards the margins; under margin crenelate. 
Anterior adductor scar pear-shaped, posterior one subcircular. Hinge: 
left valve with a strong tooth 2 and a thinner 4b, as well as an 
anterior and 2 posterior thin laterals; right valve with a strong 3b, 
very thin 3a and 5b and 2 anterior and 1 posterior indistinet laterals. 
