Kei-islands. Besides Heteroc. ensifer still three other species occur in the West-Indian seas, 

 viz. Heteroc. oryx A. M.-Edw. from the Gulf of Mexico, Heteroc. laevis A. M.-Edvv. from off 

 Martinique and Heteroc. Alexajtdri A. M.-Edw. from Havannah : the last mentioned form has 

 also been recorded from the Hawaiian Islands. While the western Atlantic is inhabited by four 

 species of this genus, only one is known from the eastern, namely Heteroc. Grimaldii A. M.-Edw. 

 and Bouv., which was taken by the "Talisman" near the Azores. 



By far the largest number of species are, however, found in the Indopacific and of these 

 the majority occur in the Indian Archipelago. No less than 8 species indeed, including the 

 already mentioned variety parvispina of Heteroc. eiisifer A. M.-Edw., have been obtained 

 by the "Siboga". Of Heteroc. Wood-masoni Alcock, a species hitherto still only imperfectly 

 known by two young individuals from the Andaman Sea, 27 well-preserved specimens were 

 collected in Madura Strait, the Bali Sea, off Makassar and near the Kei-i.slands. Heteroc. 

 tricarinatus Alcock & Anderson, hrst observed in the Arabian Sea and afterwards also near 

 East London, Cape Colony, was taken south of Muna Island and at the entrance of the Gulf of 

 Boni. The closely related Heteroc. gibbosus Bate, first discovered by the "Challenger" off Tablas 

 Island, one of the Philippines, was captured in the Bali Sea, at the southern entrance of the 

 Strait of Makassar and near the Kei-islands, where several specimens were collected : this species, 

 however, is also fairly common in the Andaman Sea, the Bay of Bengal and the Arabian Sea, 

 off the Travancore coast. Heteroc. lepidus, one of the two new species obtained by the "Siboga", 

 occurs in the Flores Sea and near the Kei-islands. Heteroc. laevigatus Bate is known from East 

 London, Cape Colony, from the Arabian Sea, from the Banda Sea, from off Banda Islands and 

 ranges as far as the Hawaiian Islands. Heteroc. signatus Rathb. is still only known from the 

 Hawaiian Islands, Heteroc. luiicarinatus Borr. only from off Providence Island, north of Mada- 

 gascar and Heteroc. longirostris Mac Gilchrist onl)- from the Baj- of Bengal. The 3 or 4 

 remaining species are those, in which two or three abdominal terga are produced posteriorly 

 into overhanging spines. In the first place the interesting new Heteroc. Sibogae, of which 42 

 fine and well-preserved specimens were collected in various parts of the Archipelago, a form 

 which is related to Heteroc. ensifer A. M.-Edw. : it occurs also in the Andaman Sea. Heteroc. 

 dorsalis Bate, first discovered by the "Challenger" off Banda Islands, was taken by this 

 e.xpedition at no less than eleven Stations in various parts of the Archipelago, from the Bali 

 Sea to Menado and the Kei-islands. The closely allied Heteroc. affinis Borr. is still only known 

 from Saya de Malha in the Western Indian Ocean, Heteroc. Alpho7isi Bate, finally, taken by 

 the "Challenger" south of the Philippines and off Japan, occurs also in the Andaman Sea, the 

 Bay of Bengal and the Arabian Sea and has even been observed off Cape Natal: it appears, 

 however, somewhat doubtful whether this form and Heteroc. afjitiis are indeed different from 

 Heteroc. dorsalis Bate. 



Three species, finally, occur on the west coast of America, firstly Heteroc. vicarius 

 Faxon, the representative of the indian gibbosus and which has been taken in the Gulf of 

 Panama, furthermore two closely related species, Heteroc. hostilis Faxon and Heteroc. afjitiis 

 Faxon, representatives of Heteroc. dorsa/is and Alphonsi: of these two Heteroc. hostilis is also 

 found in the Gulf of Panama, the other off Acapulco and near Las Tres Marias. 



SIliOGA-EXI'EDniE XXXlXil'. 2° 



