MR BAIRD ON THE ENTOMOSTRACA OF BERWICKSHIRE. 97 



In the arrangement of the genera I have followed Latreille in Cuvier's 

 Eegne Animal ; hiit with regard to species I have taken Muller as my 

 text-book, along with Desmarest in his work on the Crustacea. Lat- 

 reille divides the Entomostraca into two Orders, the Brancldofoda and 

 the Pacilopoda. The order Branchiopoda he divides again into two 

 principal sections, the Lophyropa and PhjUopa ; to the first of which I 

 for the present confine this catalogue. 



Class ENTOMOSTEACA— Order BEANCHIOPODA. 

 Section I. LOPHYROPA. 



Genus I. Cyclops. 



1. Cyclops sfaphylinus, Desmarest. — C. mintdus, Mnller, p. 101, tab. xvii. fig. 



1-7. — Canthocarpus staphylinus, J. 0. Westwood, MS. Common in pools of 



fresh water and ditches. The figure of this species, as given by Mnller, is but 

 indifferently correct ; I have therefore sketched it as it has occurred to me. PI. 

 II, fig. 1. Desmarest calls it "staphj'linus," from its habit of turning up its tail 

 like the staphylinus. From some difference in the antennae, and from the ped- 

 uncle attached to the tail, it has been proposed to form a particular division for 

 this species. My friend Mr Westwood has formed a new genus of it, which he 

 calls " Canthocarpus." PI. II. figs. 19, 20, are the young of this species in 

 different stages. 



2. Cijclops ruhens, Muller, p. 104, tab. xvi. fig. 1-3. — C. castor, Desmarest. — 



Disptomus castor, J. 0. Westwood, MS. Found in Dunglass Pond, and about 



Yetholm. It has been proposed to form a distinct group for the reception of this 

 species, from the division of the inferior antennae and palpi. It has been formed 

 into a new genus by Mr Westwood, and called Disptomus. PI. II. fig. 2 is the 

 young of this species, a few hours after birth. 



3. C. lacinvJatus, Muller, p. 105. tab. xvi. fig. 4-6. — C. castor, Desmarest. 



Found iia Yetholm Loch, along with C. ruhens. Desmarest makes the C ccernleus, 

 ruhens, and lacinulatus, into one species, which he calls C. castor, the laciniae of 

 this species being considered infusory animalcula attached to the tail. If it be 

 a mere variety, it is somewhat curious that these animals should adhere only 

 to this species, and that they should occur the same in Scotland as in Denmark. 



4. C. vulgaris, Desmarest. — C. quadricornis, Muller, p. 109, tab. xviii. fig. 1-14, 

 — Pedictdus aqnaticus, Baker, Microsc. p. 496, tab. xv. fig 1-4. — Monoculus 



quadricornis, Linne, Fabi-icius, and Donovan. Very common in all pools, 



ditches, &c. throughout the district. Desmarest has changed the name of this 

 species from quadricornis to vulgaris, and much for the better, as the epithet 

 quadricornis would lead one to suppose that this species alone had four antennae, 

 whereas all the species we know have that number. PI. II. fig. 3, is the young 

 of this species twenty-four hours after birth ; and fig. 21, three weeks old, being 

 the Nauplius saltatoj-ius of Muller. 



5. C. minuticornis, Muller, p. 117, tab. xix. fig. 14, 15. Pools of sea-water at 



Cockbnrnspath and Berwick. The young is the Amymone thyas of Mnller, p. 47, 

 tab. xi. fig. 16, 17. 



6. C. brevicornis, Muller, ji. 118. Pools of sea-water at Cockburnspath. 



7. C. Johnstoni. Nova species. PI. II. fig- 4. — Pools of sea-water at Berwick 



and Cockburnspath. Body of four segments, tail of six, terminated by two 



short lobes, from which issue two long setae, fully the length of the body. 

 Superior antennee of about six articulations, stronger than inferior pair. In the 

 male there is a bulla about fifth articulation. In the female they are more 

 slender, more setiferous, and destitute of bullae. Inferior antennae of three or 

 four articulations ; terminated by two or three short sette. All four antennae 

 setiferous at base of articulations. Head beaked. Beneath the antennae are two 

 organs (palpi ?) of two articulations, setiferous at base of articulations and at 

 extremities. Beneath these are two organs, which Muller calls hands, of two 



