376 Carcinological Fauna of Inclin. 



and the fourth (last) pair much the shortest and weakest of all. TLe 

 dactjlus in all is broad, stout, and laterally compressed. 



The abdomen in both sexes consists of 7 separate segments, and in 

 tbo male is narrower at base than the breadth of the sternum. 



Key to the Indian species of Macrophthalmus. 



I. Carapace much broader than long, its sides are distinctly 

 convergent posteriorly and the antero-lateral angles are acute 

 and spiniform : front nari'ow : — 



1. The eyestalks project nearly half their length beyond 



the antero-lateral angles of the carapace M. rerreauxi. 



2. The eyestalks project slightly beyond the antero-lateral 

 angles of the carapace : the true first tooth of the 

 lateral border of the carapace belongs to the upper 

 border of the oi'bit, and the antero-lateral angle of the 



carapace is formed bj- the true second tooth M. fiulcatiia. 



3. The eyestalks do not project bej-ond the antero-lateral 

 angles of the carapace : — 



i. Some of the borders of some of the leg joints 



are denticulate or spiny..... M. pectinipes. 



ii. Legs smooth, except for a small subterminal 

 denticle on the anterior border of the meropo- 

 dites M. convexiis. 



II. Carapace broader than long, its sides are parallel :— 



1. The tooth at the antero-lateral angle of the carapace 

 is truncate and sqnare-cat : front about an eighth the 

 gi-eatest breadth of the carapace : inner surface of the 



palm of the male smooth M. depressiis. 



2. Front about a fourth the greatest breadth of the 

 carapace : inner surface of the palm of the male 



armed with a spine • M. erato. 



III. Carapace broader than long, its sides divergent posteriorly : 

 two nearly parallel, obliquely longitudinal, finely beaded 

 lines on the posterior part of each epibranchial region M. tomentosus. 



Besides the fore-named, the four following species, of which I have not seen 

 specimens, are said to occur in Indian Seas : — 



(1) M. simplici'pes, Gnerin, Mag. de Zool. II. 1838, pi. xxiv. fig. 1 : it appears to 

 differ from M. pectiJiipes in having no spines or denticles on the leg-joints. 



(2) M. carinimanus, Milne Edwards, Hist. Nat. Crust. II. 65, and Ann. Sci. 

 Nat. Zool. (3) XVIII. 1852, p. 156 : it appears to differ from If. conrea!H.<! only in 

 liavino' a spine on the inner surface of the palm of the male cheliped. 



(3) M. pacificus, Dana, U. S. Expl. Exp., Crust, pt. I. p. 314, pi. six. fig. 4: it 

 appears to differ from M. erato only in not having a spine on the inner surface of 

 the palm of the male cheliped. 



M. hicartnatus, Heller, Novara Crust, p. 36, i^l. iv. fig. 2, which I am unable 

 from the descriptions to distinguish from M. 2^acillcu>>. 

 718 



