53 353 



Polycremnus verrucifer Slinipson, Smithson. Misc. Coll., XLIX, p. 49, pi. VI, 

 fig. 1, 1907 and synonymy. 



H. tyche has the carapace, wrist and palm covered with raised, flattened and 

 distinctly separated prominences, as shown in de Haan's figures (of fragifer). These 

 prominences are pitted or irregularly grooved. The type of C. tyche is in the Berlin 

 Museum; it is a small specimen 95 mm. long by 11'4 mm. wide, and is undoubtedly 

 the same as H. fragifer. 



H. thurstoni has similar flattened prominences, but fewer of them; they are 

 restricted to the anlero-lateral and suborbital regions of the carapace, the surface 

 of the wrist, and the upper and proximal half of the palm. 



H. ochtodes is without flattened prominences, but the antero-lateral protuberances 

 of the carapace are low and rounded, the wrist and supero-proximal surface of 

 the palm are covered with rounded tubercles. P. verrucifer corresponds to the young 

 of H. ochtodes. 



As these three species present no other differences, it is quite probable that 

 they were derived one from another in the order named, and it would not be 

 surprising if intermediate forms existed. The young (at least of H. thurstoni and 

 H. ochtodes) present greater inequalities of the surface than the old. 



H. tyche is not represented in the Siam collection, but the other species were 

 taken as follows: 



Halimede thurstoni Henderson. 



Plate I, fig. 19. Plate II, fig. 7. 



Between Koh Kut and Koh Kahdat, 10 fath., shell bottom; I. 10; 1 c? juv. 1 juv. 

 Koh Kam, 5 fath., gravel; II. 6; 1 Ç jnv. 2 juv. Between Koh Mesan and Cap 

 Liant, 5 — 8 fath., sand, stones; II. 7 ; 1 c? juv. Koh Chuen, 30 fath., shell bottom; 

 II; 1 c? juv. 1Ç juv. with Rhizocephalid. Between Koh Rin and Clifl" Rock (N. of 

 Koh Kram), 15 fath.; III. 2; 2 juv. N. of Koh Chuen, 15 fath., mud, shells; II. 5; 1 juv. 



Halimede ochtodes (Herbst). 



Plate I, fig. 4. 



The gulf at Rayong, 7 — 10 fath., sand, mud, shells; II. 8; 1 ? ovig. Koh 

 Kahdat, 4—5 fath., sand, stones, coral; II. 15 — 18; 1? juv. Koh Chuen, 30 fath., 

 shell bottom; II; 1 c? with large Rhizocephalid. Koh Lan, 30 fath., mud; III. 2; 

 1? juv. 



In young specimens the lateral projections are more acute than in the adult. 



Length of ovigerous Ç 31 mm., width 42 6 mm. 



This species has been recorded at Hong Kong (Stimpson), Singapore (Walker), 

 Penang (Alcock), Madras Coast (Alcock), East India (Herbst), Indian Ocean (AdaiMS 

 and White). 



