of the Family Halacaridae. 183 



reux) upon Algae (Corallines &c.) , very common. Baltic : 

 Kiel and Gotland (Lohmann) upon Red Seaweeds (at 12 

 fathoms) and on Green Seaweeds. 



8. Halacarus ctenojms. 



H. ctenopu.*, Gosse (1), p. 28, pi. iii. figs. 6-10 : Brady (3), p. 310 ; 

 Lohmann (8), p. 77. 



Char. Like the preceding species, but smaller and more 

 elongated, and never presenting the dark colour of the adult 

 H. spinifor. Epistome with an acute anterior point. Claws 

 of the first pair very similar to those of the others. Claics of 

 the third and fourth pairs destitute of ciliated combs, while 

 those of the other two pairs (2 and 3) are provided with them. 

 Anus terminal. A notogastric plate. TJngueal groove but 

 slightly developed, as in the preceding species. Total length 

 0'80 millim. 



Bab. French coasts (rare) : Le Croisic (Chevreux), on 

 floating seaweeds. Coasts of England and Ireland, the Shet- 

 land islands, Scilly, &c. (Gosse, Brady), at depths varying, 

 according to the localities, from 7 to 35 fathoms (littoral, 

 Laminarian and Coralline zones). 



9. Halacarus actenos, sp. n.* 



Char. Very like the preceding species, but all the claws 

 destitute of ciliated combs. No notogastric plate. Epistomial 

 plate terminating behind in a triangle. No ungueal groove 

 on the tarsi. Total length from 0"65 millim. (male) to 0*75 

 millim. (female). 



Hab. French coasts (Atlantic), scarcer than H. spiniger, 

 but more generally distributed than H. ctenopus : Le Croisic 

 (Chevreux), Baie de Port-lin, on Fucus serratus ; Arcachon, 

 on oysters (Trouessart) ; Saint Jean-de-Luz (Neumann), on 

 Alga? (a male individual more brightly coloured (orange-red) 

 and with shorter limbs than the males from Le Croisic) . 



10. Halacarus Harioti, sp. n. 



Char. Epistomial plate forming a very obtuse angle in 



* This species may perhaps be the Halacarus ctenopus ? of Grube {H. 

 frontispinis in the text), found by that naturalist at Roscoff (Abhandl. 

 'schles. Ges. Xaturw. 1868, pp. 123, 124) and described as resembling 

 H. ctenopus, but with non-pectinate ciaws. However, Grube savs formally 

 that he did not see, on the penultimate joint of the palpi, the' short and 

 strong spine which characterizes H. actenos as well as H. ctenopus. 



