A Synopsis of the Recent British Ostracoda. 123 



terminal claw very large and strong. Eyes wanting. Shell thin 

 and pellucid, subovate, truncate behind. Marine. 



I. prcetexta, G. 0. Sars. — This curious species is at once 

 distinguished by its elongated ovate form and truncate pos- 

 terior extremity, which is also centrally emarginate. It occurs 

 very sparingly in our seas, having been found only on the 

 Dogger Bank and on the west coast of Scotland. The absence 

 of eyes is accounted for by its habit of burrowing in soft 

 mud. 



Loxoconcha, G. 0. Sars. — Upper antennae very slender, 

 six-jointed, the last joint very long, linear, and bearing only 

 long, simple setae. Lowest seta of the branchial plate of first 

 jaw defiexed. Feet long and slender, alike in male and female. 

 Abdomen terminated by a hairy conical process ; post-abdo- 

 minal lobes bearing two long subequal setae. Shell sub- 

 rhomboidal or peach-stone shaped, surface mostly marked 

 with regular concentric pittings and small papillae, sometimes 

 with deep polygonal excavations ; posterior dorsal angle 

 obliquely truncate. Hinge formed by four small teeth, two on 

 each valve. 



L. impressa (Baird) ; granulata, Sars; elliptica, Brady; 

 tamarinclus (Jones), guttata (Norman). 



Identical with the genus iSTormania, described by me in the 

 "Transactions of the Zoological Society of London," Vol. v. : 

 the name Loxoconcha is however of prior date. The species 

 are all marine, except L. elliptica, which inhabits brackish 

 water.* 



Xestolebeeis, G. 0. Sars. — Upper antennae six -jointed, the 

 last four joints gradually decreasing in length and bearing 

 very short, simple setae. Feet short, post -abdominal lobes 

 bearing two setae. Ova and immature young borne within the 

 shell of the female. Shell smooth and polished, ornamented 

 with small round papillae, depressed in front, in the female 

 very tumid behind. Hinge formed by a dentated crest of the 

 left, which is received into a corresponding excavation of the 

 right valve. 



X. aurantia (Baird) ; depressa, G. 0. Sars. — Zenker and 

 Sars both agree in the statement that the animals of this genus 

 are viviparous ; a point which I have myself had no opportu- 

 nity of investigating. 



X. depressa is a common inhabitant of deep water, while 

 X. aurantia is found almost exclusively between tide marks. 

 The former is pearly white, exhibiting most beautiful iri- 

 descent tints, and sometimes deeply tinged with red at the 

 anterior extremity. The latter is yellowish brown in colour, 

 and has no iridescence. 



* The remaining genera are entirely marine. 



