NEW CRUSTACEAN OF THE GENUS MYSIS. 329 



This species approaches very near to M, oculatus, O. Fabr. 

 (Cancer oculatus, On Yah. Faun, Groen., p. 245; Mysis Fabricii, 

 Leach, Linn. Trans., vol. xi., p. 350" Thompson, Zool. Res., 

 pt. 1), and may prove to be synonymous with it. 



Rock pools, Penzance. — Couch. Falmouth. — Norman. 



Mysis spiritus, n. s. (PI. XYIL, figs. 1, 1*.) 



Mysis gracilis^ pellucidus^ vitreus. Tliorax cylindricus. Abdomen 

 a thorace ad caudam gradatim diminuens ; abdominis segmentum 

 penultimmn longius quam ccetera. Appendix antennarum 

 squamiformis suhtriangularis, apiceacuto; spina in medio mar- 

 ginis exterioris px^sita; margo interior atque exterior supra 

 spinam dense ciliati ; margo exterior suh spina non ciliatus. 

 Thoracis frons vix rostrata, fere suhtruncata, Pedunculi 

 ocidorum longi, appjendicisque antennarum dimidiiim superantes 

 Antennas breves , thorace vix longiores. Telson apicefisso inter- 

 medias fere cequat lamellas; fissura brevis. 



A perfectly colourless, glassy, transparent species, and, like ilf. 

 Oberon, scarcely to be distinguished except by its black eyes ; 

 very slender in form. Carapace cylindrical, not widening behind. 

 Abdomen gradually tapering towards the tail. T\\q, front margin 

 of the carapace can scarcely be called rostrate, being very nearly 

 truncate. Antennal scale subtriangular, with the apex acute, not 

 twice as long as the long peduncle of the eye, and slightly 

 exceeding the peduncle of the interior antennse ; a spine placed 

 halfway up the exterior margin; inner and outer margin above 

 the spine densely ciliated; outer margin below the spine plain. 

 AntenncE remarkably short, not so long as the carapace; the 

 peduncles of the interior exceed in length their filaments. Telson 

 two-thirds the length of the intermediate laminae ; the bifurca- 

 tion is through about a third of its length. 



A few specimens taken in sandy rock pools, at Black Hall 

 Rocks, on the occasion of the meeting of the Field Club, at 

 Castle Eden, on the 27th of June. 



The following diagnosis may be usefully borne in mind by the 

 Carcinologist : — M. Lamornce has no spine on the antennal scale ; 



