A MONOGRAPH OF THE SEA-SNAKES (HYDROPHIINM). 



243 



the British Museum, the preocular is confluent with the prefrontal on both sides. In 

 another I obtained from Madras the prefrontals fail to meet one another owing to 

 the forward projection frontal. 



Habitat. — All were captured along the shores between Ceylon and Penang. 



ACALYPTUS. 



Acalyptus peroni (Dumeril et Bibron). 



Acalyptus superciliosus — 



vel peroni, Dumeril et Bibron, Erp. Gen. Hist. Nat., vii, p. 1340. 

 Acalyptus peronii, Dumeril in Mem. Acad. Sc. Paris, 1853, xxiii, p. 522. 

 Acalyptophis superciliosus, Giinther , Rept. Brit. Ind., 1864, p. 359. 

 ,, ,, Jan, Icon. Gen., 1872, 40, pi. ii, fig. 2. 



,, peronii, Boulgr., Cat., iii, 1896, p. 269. 



Fig. 59. — Acalyptus (superciliosus) beroni. After Jan, Icon. Gen., 40, pi. ii, fig. 2. 



I have examined three specimens only, all in the British Museum. The two 

 examples presented by Dr. Giinther, and the Earl of Crawford appear to me alike, but 

 that presented by Dr. Fischer will, I think, prove to be a species apart. In the last 

 named the costals are 19 anteriorly, 24 in midbody, and 2^ posteriorly. The ventrals 

 156, and narrower than the last costal row. On the other hand the two former have 

 23 costal rows anteriorly, and 29 in the mid and posterior parts of the body. The 

 ventrals are 195 ? and 209, and about as broad as the last costal row. Fischer's 

 specimen is from Hong-Kong. The habitat of Giinther's is unknown, and the Earl of 

 Crawford's is from Torres Straits. I think Fischer's specimen should be given specific 

 rank, but there being only one specimen I prefer to follow Mr. Boulenger's ruling in 

 the matter. 



Description. — The head shields are studded with asperities. 



Rostral, — in contact with four shields, the portion visible above about two-thirds 

 the internasal suture. Prefrontals, — touch no supralabial. Frontal, — broken up. 

 Parietal s, — broken up . Nasal s , — touch the first and second supralabials ; nostril 

 in the nasal shield, a suture runs from it to the prefrontal, and another to the second 

 supralabial, so that the shield is divided into two parts. The detached fragment, how- 

 ever, is obviously a part of the nasal, and not a separate shield. A similar condition 



