416 M. E. Hesse on the Pranizse and Ancei. 



by the author to live solely on the shore ; at least they under- 

 went their metamorphosis in his aquaria without having attached 

 themselves to fishes : these areAnceus Brivatensis and A.Manti- 

 corns. The individuals of various species kept by the author, 

 some of which existed in captivity for more than two years, fed 

 upon decomposed sea-weeds or upon the minute animals which 

 might be met with amongst these and in the sea-water with 

 which the vessels in which they were preserved were filled. 



Classification of the Ancei. 



The systematic position of the Ancei, in the author's opinion, 

 is between the parasitic Cymothoadce and the Epicarides, the 

 latter being, like them, suctorial Crustacea. From the SpJiaro- 

 mida, with which they have been placed, they differ in the 

 structure and arrangement of the respiratory organs, in the pre- 

 sence of the large mandibles in the male, in the great size of 

 the head in the same sex, in the form and structure of the an- 

 tennae, and in the conformation of the buccal organs. The 

 Sph(B7'omidcE have seven thoracic segments and seven pairs of 

 thoracic limbs ; in the Ancei the number of these segments and 

 pairs of limbs is only five : the Ancei have a narrow abdomen, 

 composed of six perfectly separate segments; whilst the Spharo- 

 midcB have only two or three segments in this region of the body, 

 and even these are generally soldered together. The two groups 

 are further distinguished by the nature of the integuments, and 

 especially by the mode in which the eggs are carried previously 

 to the exclusion of the young. In the Spharomidce they are 

 contained within the carapace ; but in the Ancei they are placed 

 outside the body, beneath the membranous laminse which spring 

 from within the thoracic feet and, by lying over each other, 

 form a large incubatory pouch. The author also calls attention 

 to the analogy presented by the female Ancei with those of 

 Ourozeuktes. 



In the present paper M. Hesse describes eleven species of the 

 genus Anceus, several of them as new ; but he complains that, 

 from the imperfect descriptions of previous authors, he has often 

 found it impossible to identify their species. He divides them 

 into four sections, characterized by the form of the large laminar 

 mandibles of the males : — 



1. Mandibles in the form of nippers, denticulated only at their 



extremities. 

 A. Formica; A. Brivatensis. 



2. Mandibles hatchet-shaped ; their inner margins without 



denticulations. 

 A. asciaferus. 



