386 REV. A. M. NOMTAN AND MK. G. S. BEAD? 



remarkably erect, anterior antennae reaching the extremity of 

 the rostrum; tentacular hairs very long. Eye-spot very large. 

 Abdomen very large and deep, supero-posteal angle completely 

 rounded off ; instead of -being furnished with a single line of 

 lateral spines, as is usual in the genus, this species has the mi- 

 nute spines which are on the anterior portion gradually increas- 

 ing in size, and arranged posteriorly in groups of two or three 

 spines each, which are of different lengths, each group of spines 

 being placed in an oblique direction on the side of the abdomen ; 

 abdominal claws long, slender, and simple (not furnished with 

 any spine). Length, ^-th of an inch. 



The circumstances under which we are enabled to give this 

 species as a member of the British Fauna are so remarkable, that 

 we venture to give them at length. One of the authors of the 

 present paper (A.M.N.) brought home, one afternoon in the sum- 

 mer of 1864, a bottle of water, containing a large quantity of 

 Entomostraca, from a pond in Lambton Park, county of Durham. 

 The gathering was almost entirely composed of a mass of Daphnia 

 pulex. "While examining this gathering, under the microscope, 

 a portion of the abdomen of a Lynceus floated across the field, 

 which at once struck him as different from anything known in 

 Britain before ; but at the same moment it flashed across him 

 that he had seen and made a tracing of the figure of such an 

 abdomen; and, taking down a M.S. book from his library, he 

 found that the portion of the Lynceus which he had found agreed 

 exactly with the figure of Fischer's Lynceus acanthocercoicles, pub- 

 lished in the Bulletin of the Imperial Society of Naturalists at 

 Moscow. Greatly interested in this discovery he carefully passed, 

 drop by drop, under 'the microscope, the whole of the gathering 

 obtained, in the hope of obtaining perfect specimens. He was so 

 far successful as to find a cast slough of a carapace, apparently 

 that to which the abdomen had belonged, and this entirely bore 

 out the identity of the species with that of Fischer. No perfect 

 specimen could however be found, and subsequent visits to the 

 pond bave as yet proved equally unsuccessful. Since no perfect 

 British specimen has as yet been met with, the figures given of 

 this species are copies from Fischer. 



