in the Cephalopoda. 89 



males of which are represented in figs. 5 & 6, and which are 

 easily distinguished from each other by the different size of the 

 acetabula on the second and third arms, the left ventral arm is 

 also metamorphosed, but in a far higher degree than in the two 

 preceding genera, as throughout its whole length it has not the 

 least trace of a sucker, the surface on which the suckers should 

 be situated being even converted into a compressed, obtusely- 

 toothed edge ; we find that all the teeth of this edge are pro- 

 duced from the fused bases of the peduncles of the inner series 

 of acetabula, whilst of those of the other row scarcely the smallest 

 trace is left. Fig. 5' represents the left ventral arm of Loliolus 

 typus, Stp., seen from the outer side, and somewhat enlarged; 

 the small projecting points are the only traces of the suckers 

 and peduncles of the outer series. Fig. 6' represents the same 

 arm of Loliolus affinis, Stp., also magnified ; on this I have been 

 quite unable to find any such points, but cannot assert that they 

 are entirely wanting, as the specimen is unfortunately rather 

 flabby. The number of metamorphosed suckers may have been 

 about twenty-six in the former and twenty in the latter, to 

 judge from the number of the teeth*. 



With D^Orbigny, as is well known, the genus Sepia belongs 

 to quite a different group from the preceding genera ; but still, 

 in this genus, it is the same pair of arms which presents the want 

 of symmetry in the male individuals, and the arm of the same 

 side which is metamorphosed, but instead of the apex or apical 

 half of the arm being the seat of the transformation, it is here 

 the basal part or the lower half. ;'ii>ji aidi^togr^t; 



Thus, if we compare the right and left ventral arms in a male 

 Sepia officinalis, Linn., we shall see at once, that the lowest 

 fourth part of the left arm (as shown in fig. 7) has a peculiar 

 appearance. Whilst the right arm has large and perfect aceta- 

 bula, which follow each other in four complete rows, and increase 

 in size from the apex of the arm inwards towards its base, the 

 above-mentioned part of the left arm has only the two or three 

 lowermost suckers in each row normally developed, whilst the 

 seven or eight following suckers in each row have either become 



* For the more exact determination of the species, I may also state that 

 both have a broad, free, internal gladius, which has the greatest resemblance 

 in form to those of Loligo brevis and L. brevipinna, figured by D'Orbign}^ 

 tab. 13. fig. 6, and tab. 15. fig. 3. In the species of Loliolus, however, 

 the lamina is perhaps rather broader in proportion to the shaft ; the shaft 

 has a sharp keel in L. typus, whilst both males and females of L. affinis 

 have the shaft rather broader, and with a more rounded back. I have no 

 indication of locality for ray Loliolus typus ; Loliolus ajffinis occurred in a 

 glass marked " Ca})tured by Governor Cliristensen on the voyage from the 

 Cape to Tranquebar," so that it is an inhabitant of the Indian Ocean. 

 There were two specimens, male and female. 



