OCR Text |
Show 198 DR. W. T. CALMAN ON THE MACRUROUS [Mar. 6, thirds of length of carapace, horizontal, teeth 2"\^~', unarmed above for one-fourth of its length. Antero-lateral spine of carapace small, set close to front edge. Antennular peduncle a little shorter than antennal scale. Distal edge of scale (Plate XIII. fig. 39) not projecting so far as the external tooth. Third maxillipeds not reaching to end of second segment of antennular peduncle, terminal segment a little shorter than preceding. First peraeopods (Plate XIII. fig. 40) short and stout, not reaching middle of first segment of antennular peduncle, breadth of carpus about two-fifths of its length; chela one and a half times as long as carpus, two and a half times as long as broad, palmar portion slightly shorter than fingers. Second peraeopods (Plate XIII. fig. 41) not reaching end of first segment of antennular peduncle, breadth of carpus one-fifth of its length; chela equal to carpus, about four times as long as broad, palmar portion little more than half of length of fingers. Third peraeopods reaching well beyond, fifth pair falling short of tip of third maxillipeds. Merus of last three pairs with two, sometimes three, spines on distal part of the lower margin, carpus with two spines side by side. Dactylus in each case a little less than one-third of length of propodus, that of third pair (Plate XIII. fig. 42) with five, that of fifth (Plate XIII. fig. 43) with twelve spines. Telson (Plate XIII. fig. 44) a little shorter than sixth abdominal somite. Outer plate of uropods a little shorter than inner. Total length 7 m m . Eggs *25 x '15 m m. Remarks.-This species resembles the preceding very closely, but the distinguishing characters are constant in all the specimens examined. Occurrence.-Niamkolo Harbour, 7.ix.04. " Dredged in about 3 fathoms, among shells." Two specimens. Kirando, l.xii.04. " Taken in about 8 fathoms of water. among shells." Many specimens. Utinta, 6.xii.04. " Dredged in about 15 fathoms among shells." Twelve specimens. Genus CARIDELLA, gen. nov. Peraeopods without exopods; carpus of first pair excavated distally, that of second pair not excavated; chela? of both pairs with a distinct palmar portion. Epipods on the first three pairs of peraeopods. No pleurobranchia on the last thoracic somite. Type, C. cunningtoni, sp. n. This new genus is intermediate to some extent between Caridina and Limnocaridina. It resembles the former in the general structure of the mouth-parts, in the presence of an outer plate on the first maxilla and of a minute epipocl on the first maxilliped. It approaches Limnocaridina in the reduction of the branchial system and especially in the absence of the posterior pleurobranchia, while several of the gills in the anterior part of the branchial chamber are also absent or reduced to small vestiges. |