554 Transactions. 



Chlamys cellularis n. sp. Fig. 46. 



Description of Type Specimen. — Left valve triangularly orbicular, flatly 

 rounded. Anterior ear one-third the length of the shell, triangular, its outer 

 edge sinuous, a shallow groove and sinus at its inner margin. Posterior 

 ear narrowly triangular. Disc with the dorsal margins sharply descending, 

 very slightly concave ; rounded and descending somewhat along the an- 

 terior, basal, and posterior margins, which are slightly crenulate. Resilifer 

 obliquely triangular. The epidermis usually persists, especially in the 

 interstices between the ribs, as a cellular covering, giving the shell a cha- 

 racteristic honeycomb appearance. Sculpture : Anterior ear with 6 radiating 

 ribs, the 3 outer ones broad and flattened, the 3 inner ones about half the 

 width of the outer. Posterior ear with small radiating ribs. Disc with 

 15 principal radiating ribs, the 2 central ones are smaller than the others. 

 The upper surface of the ribs divided by 2 grooves into 3 riblets, of which 

 the central one is largest. In the interstices are 2 riblets in the angles at 

 the bases of the principal ribs, leaving a wide and deep channel in the centre, 

 and grooves the width of the riblets between them and the principal ribs. 

 The surface of the shell presents a microscopically reticulated appearance, 

 apparently due to the growth of the epidermal covering. The marginal 

 portion of the riblets has a series of projecting shelly scales. Interior 

 prominently grooved. Colour white, diffused with pink, chiefly on the ribs, 

 and as 3 concentric broad bands on the upper portion of the disc. Base 

 of ears with pink blotches. 



Diameter — Ant.-post., 18-5 mm. ; dorso-ventral, 20-2 mm. 



Variations from, Type. — Right valve with the anterior ear oblong, 

 obliquely truncated, a deep byssal sinus below ; posterior ear narrowly 

 triangular. The colour is variable. The irregular pink markings are present 

 on all the specimens seen, and are arranged in more or less defined con- 

 centric bands. The ground-colour on one shell is lemon-yellow. 



Habitat. — The only specimens obtained were single valves found on the 

 beaches at Sunday Island. 



Fossil. — A valve apparently referable to this species was found on Deyrell 

 Islet in hard sandy tuffs of submarine origin. (Pecten kermadecensis Oliver, 

 Trans. N.Z. Inst., 43, 527, 1911.) 



Limatula bullata (Born). 



Ostrea bullata Born, Mus. Caes. Vindobin, 110, 1780. 

 Recorded, Iredale, Pro. Mai. Soc., ix, 72, 1910 (Lima). 



Habitat. — Valves common in dredgings in 10 m. to 30 m. near Sunday 

 Island. 



Distribution. — New Zealand, Tasmania, Australia, Pacific, Philippines. 



Limatula insularis n. sp. Fig. 47. 



Description of Type Specimen. — Shell ovate-oblong, very slightly oblique, 

 ventricose, posterior end slightly more convex than anterior end. Beaks 

 incurved, distant. Ears small, nearly equal. Hinge area straight, lenti- 

 cular. Sculpture : On each valve are 12 rounded radiating ribs, the inter- 

 stices and ribs about equal in width. These are crossed by close concentric 

 growth-lines, and, near the margins, projecting shelly scales, most prominent 

 at the posterior and anterior ends. Colour white. 



Diameter — Ant.-post., 2-3 mm. ; dorso-ventral, 3-5 mm. Thickness, 

 2-1 mm. 



