116 



J.A. ALLEN AND H.L. SANDERS 



Fig. 21. Ledella aberrata. Five shells in outline to show variation in 

 shape with growth, a, is a specimen with a thickened margin; b. has a 

 slightly thickened margin; the remaining three shells are unthickened. 

 Scale = 1mm. 



same route. Unlike the latter species, it makes a single coil on the 

 right side as well as a double twinned coil on the left. 



The foot is unusual in having a large heel and a narrow muscular 

 anterior part. The marginal papillae are few in number and restricted 

 to the anterior margins of the sole. The sole is less deeply divided as 

 compared with other protobranchs. There is a large 'byssal' gland in 

 the heel of the foot. 



Although the shell outline of the smaller specimens is more 

 characteristic of the genus Ledella than in larger mature specimens, 

 the general shell outline of L aberrata (and L. acinula) is much 

 deeper and more ovate than in other described species (Figs 1 8 & 2 1 ) 

 nor is it markedly rostrate. Despite this, the characters place them in 

 the Ledellinae (Allen and Hannah, 1989) and we see no reason for 

 erecting another genus. 



Apart from L. aberrata, only two species of protobranchs, have 

 been reported as exhibiting a change in shell growth to produce a 

 flattened shell margin (Fig. 20). Both are ledellids, namely L. ultima 

 (Smith 1885) and L. solidula (Smith 1885) (Allen and Hannah, 

 1989). Like L. aberrata these two latter species also have elongate 

 hind guts. The hind gut of L. solidula is very similar to that of L. 

 aberrata in having double twinned coils to the left side of the body 

 (Fig. 22), although it does not have an additional single coil to the 

 right as does the present species. The type of course taken by the 

 hind gut in L. acinula is also found in other species of Ledella (e.g. 

 L. oxira) (Allen and Hannah, 1989). 



We named this species after the familiar appelation to which it 

 was referred during our original analysis of the samples. 



Tindariopsis agatheda (Dall 1889) 



Type specimen. USNM 95437, lectotype here designated. 



Type locality. U.S. Fish Commission Sta. 2754, east of Tobago, 

 1 1°40'N 58"33W, 1609m. 



Fig. 22. Ledella aberrata. Internal morphology as seen in a, right lateral 

 view, b, left lateral view and c, left ventro-lateral view. For identification 

 of the parts see text-figure 7, p. 106. Scales = 1mm. 



Cited specimen. BMNH 1995062. 



Malletia (Tindaria) agatheda Dall 1890, 252, pi. xiii, fig. 10. 

 Tindaria (Tindariopsis) agatheda Verrill and Bush 1897, 59. 

 Saturnia (Tindariopsis) agatheda McAlester 1969, N235. 

 Tindariopsis agatheda James 1972, 98, figs 60-62. 

 Neilonella (Tindariopsis) agatheda Laghi 1986, 190, pi. 8, figs 2-6. 



Material: 



Cruise 



Sta Depth No Lat 

 (m) 



Long 



Date Gear 



BRAZIL BASIN 



Atlantis II 167 943- 1 07'58.0'S 34'28.0'W 20.2.67 ES 



31 1007 



GUYANA BASIN 



Knorr25 293 1456- 14 08"53.1'N 54'04.3'W 27.2.72 ES 

 1518 

 299 1942- 8 0T55.1'N 55°42.0'W 29.2.72 ES 



2067 

 301 2487- 7 08"12.4'N 55'50.2'W 1.3.72 ES 

 2500 



The type specimen has been examined by us. 



