and Species of Niulihrnnrhiate. }foUuiirn. H.*) 



7revefi/ana concinnn, ap. nov. 1*1. \ 1 1. figs. 8, 8 a, 8 h. 



T. lupvia, in rcj^iono hraiicliiali li'vata, (lilatafa(|ue, pallio di.stiiicto 

 cnrenB,iinic(>lorata ; ti-ntaculis dorsalibus parvis rotiindatia, niinuto 

 larainatis, confortis, rotractilil)U8; braiicliiiH aexdecem, arrcctis, bi- 

 piiiimtis, iioii-retnulilibus, rncdialitor in dorso, ante et purtim 

 circum anum ])ositis ; pode ad fineni eaudoj extenso, antice cum 

 fossa transvei-sali cujiis lamina anterior lata est, ct in duos lobos 

 laeves rotundatosque UKxlialiter divisa. 



The body is eloni;ate,s(>in('wliat coiiiprosstMl laterally, convex 

 above, the central branchial re^^ion being the highest, smooth. 

 There is no indication of a mantle, nor any appendages. The 

 tlor.sal tentacles are short, ronnded and nodular, finely marked 

 with rather upright laminre, and retractile in cavities which 

 are placed close together on the head. The branchia^, fourteen 

 to sixteen, arc u})right, bipinnate, non-retractile, set on the 

 centre of the back at a little distance from and around the 

 anu."?, in an arc occujiying three fourths of a circle, the con- 

 vexity being fonvards. The integument is gently rai.sed out- 

 side the plumes. The mouth is terminal, without oral tentacles, 

 but their position is indicated by two indistinct slightly raised 

 oval surfaces placed superiorly to the o])ening. The foot is 

 linear, truncate in front, and extends behind to the end of the 

 tail, where it terminates in a point ; in front there is a deep 

 transverse groove, the anterior lamina of which is wide antero- 

 posteriorly, and divided by a median depression into two, flat, 

 rounded lobes ; the border of the foot is rather thickened and 

 free. The colour of the spirit specimen is a light semitrans- 

 parent brown, with the tentacles, the branchiae, and the foot 

 opaque. 



The length in spirit is 30 millims., the breadth 10, the 

 height 12. 



The specimens were obtained in the Gulf of Suez. 

 T. concinna appears to differ from T. ceylonica principally 

 in the absence of markings, from T. impudica in the absence 

 of dorsal tubercles, and from the other species in the shorter 

 and less depressed body. 



EXPLANATION OF THE PLATES. 

 Plate VL 



Fig. 1. Calt/cidorin Giintheri, upper surface. 1 a. Branchiae, enlarged. 



1 b. I'nder surface. 1 c. Side view. 

 Fig. 2. Hcrabranchiis pelhtcidultts, side view. 2 a. Upper surface. 2 b. 



Another specimen, side view. 2 c. Under surface. 

 Fig. 3. Hcrabranchiis sttezensia, half nat. size, seen from above. 8 a. Seen 



from below. 

 Fiij. 4. ]Hi)cai)inphiTus lurrnfu.i. 4 a. T'nder surface. 



