of the Family Halacaridse. 187 



19. HaJacarus (Leptopsalis) longipes. 

 Trouessart (7), p. 754. 



Char. Facies of the nymphs of Hal. spinifer, but pre- 

 senting the characters of the subgenus. A small spine 

 directed obliquely forward upon the inner margin of the 

 penultimate joint of the palpi. Epistome cut squarely in 

 front. Legs long, cylindrical ; claws pectinate, with a very 

 feeble lateral tooth ; no ungueal groove. Anterior legs with 

 slender seta3, sparingly spinous. Anus terminal. Total 

 length O'GO millim. 



Hab. French coast: Pas-de-Calais, Wimereux (Gia?'d), 

 on the byssus of mussels. A single individual, 2nd nymph *. 



20. Halacarus {Leptopsalis) Chevreuxi. 

 Trouessart (10), p. 162. 



Char. Body ovoid-conical, with the anus terminal. Legs 

 very nodose, with the penultimate joint pyriform. Epistome 

 short, bilobate, with a median emargination. Rostrum much 

 elongated, slender, and compressed ; hypostome very long, 

 thin, and spatuliform ; mandibles very slender, nearly styli- 

 form. Claws pectinate, with a small median piece. Tarsus 

 with an ungueal groove. The variety from the Mediter- 

 ranean has the penultimate joint of the legs rather angular 

 than pyriform. The cuirass is nearly smooth. Total length 

 0-80-0-90 millim. 



Hab. French coast : Le Croisic (collected in numbers by 

 M. Chevreux, to whom the species is dedicated), Baie de 

 Port-lin on Red Seaweeds (Florideaj), on Polysiphonia and 

 on Alcyonidium hirsutum; Baie de Croisic on Corallina 

 officinalis, Laminarian zone ; Banc de Basse-Hergo on brown 



Algffi, &c. ; Saint- Jean-de-Luz (Neumann) on Algaa. Shores 

 of the Mediterranean (Trouessart) on the Corsican moss 



(Gigartina helminthocorton) \. 



* Another Halacarid, taken by M. Chevreux at Le Croisic upon Spono-es 

 (Halichondria panicea), greatly resembles this species and has the extre- 

 mity of the palpi bifid ; but the hypostome is less spatuliform, the hairs 

 of the anterior legs are spinous, as iu H. spinifer, and there is an ungueal 

 groove. 



t A third species would appear to take its place in this subgenus, viz. : 



Halacarus olivaeeus, Grube, Abhandl. schl. Ges. Naturw. 1868, p. 121 

 pi. ii. fig. 3. This species, which we know only from Grube's figure and 

 description, approaches Leptopsalis Chevreuxi in the form of its rostrum 

 and legs. Obtained by Grube at the island of Batz, near RoscofF. 



