148 LOIMIA MONTAGUI. 



either dorsally or ventrally, though it may represent in the dorsal region part of the 

 segment in front. 



The following segment carrying the second pair of gills has a broad fan-shaped flap 

 at each side about midway between the gill and the ventral scute, whilst the following or 

 fourth segment bears the third branchia and the first setigerous process. The ventral 

 scutes in the example are not separated by the deep furrows so characteristic in other 

 forms, but appear to be nearly continuous from the anterior broad scute to the narrow 

 median ridge about the eleventh bristle-tuft. All the segments are marked by narrow 

 rings. The general colour is yellowish, the ventral scutes rufous brown shaded with 

 purplish black (Montagu). Gravier describes the forms from the Red Sea as greenish 

 grey, with bold bars of brown on each thoracic segment, and white at the insertion of the 

 dorsal bristles. The ventral tori are underlined by dark bands with a touch of the same 

 colour at the cushions. The latter are reddish. The abdominal tori are white, set like 

 pearls in a base of grey pigment. The tentacles have brown rings, The branchiaB are 

 comparatively small, distinctly separated, and with short stems, the usual gradation 

 occurring from the first to the third. They are distinguished from all the others by their 

 very finely branched terminal divisions. The main stem and its subdivisions are 

 short so that the entire organ in each case projects proportionally little. It is 

 dichotomously divided. The branchia3 of the Mediterranean L. medusae, though also 

 furnished with fine terminal ramuscules, are more lax in branching, the separate divisions 

 being longer. 



Seventeen pairs of prominent setigerous processes occur anteriorly, and the bristles 

 are directed outward and backward. Bach consists of a flattened brush, with the edges 

 dorsal and ventral, of pale golden bristles, the tips of which are in two series, a longer 

 and a shorter. Each bristle (Plate CXXVI, fig. 1) slightly dilates above its pale bulb to 

 uear the origin of the wings, then tapers to a fine point. The wings are of moderate 

 breadth, and cease before reaching the delicately tapered tip. The bristles of the shorter 

 series have the same structure, but their shafts are more slender. They extend about as 

 far as the commencement of the wings of the longer series. No noteworthy difference 

 between the first and the last tuft occurs. 



The rows of hooks commence at the second bristle-tuft, and are long in front, 

 diminishing in length backward to the ninth or tenth, and again increasing at the 

 fourteenth setigerous process, that is, behind the median frill which succeeds the scutes, 

 only a brief space separating the long rows in the mid-ventral line, and the same 

 condition is found at the fifteenth. At the sixteenth and seventeenth setigerous process 

 the rows are shorter, as also is the mid-ventral space between them. The uncinigerous 

 lamellas which succeed are almost ventral in position, being separated only by the 

 narrow ventral surface (Montagu's dorsum), and they continue to the posterior end 

 (absent in the example). Double rows of hooks occur from the seventh to the sixteenth 

 (fide autor.). 



The hooks (Plate CXXVI, fig. 1 a) have a long anterior border with four or five 

 teeth in diminishing series above the chief fang, making five or six in all, and there is no 

 process on the edge of the base beneath the main fang. The posterior outline is boldly 

 convex (opposite the teeth), curving inward to a notch which separates the irregularly 



