December 1, 1898.] 



KNOWLEDGE 



271 



of coloration met with among cowries, it may be men- 

 tioned, as a preliminary, that among mammals spots and 

 stripes are frequently met with in the young which 

 disappear in the adult. Many species of deer and swine, 

 for instance, which are spotted or striped with white in 

 youth become more or less completely uniform in mature 

 age ; while the lion and the puma frequently exhibit traces 

 of dark spotting in the cub stage. In these animals, 

 therefore, it is evident that a spotted or striped coat is 

 the original type, and a uniform tint the more advanced 

 form. In cowries, on the other hand, it seems that 

 transverse dark banding was the original type of colora- 

 tion, and that from such banded type two later modifications 

 have taken place. In the one of these, spotting of various 

 kinds has resulted, while in the other a more or less uniform 

 colour has been the final result. The primitive banded 

 type serves to connect the cowries with less specialized 

 shells, a young Surinam-toad cowry being strikingly like a 

 melon-shell, both in form and colouring, while the faint 

 banding observable in young specimens of Scott's cowry 

 recalls the colours of many of the wing-shells, to which, as 

 already mentioned, the former approximates in form. 



The proof that banding was the original type of cowry 

 coloration is easy, seeing that it obtains in the young of 

 the great majority of species. Fig. "J, >>, exhibits the striped 

 stage of the Surinam-toad cowry, which, in the adult, as 

 already said, has chestnut spots on a dark ground in the 

 central area of the upper surface. In Fig. 3, a, are shown 

 the adult and immature conditions of the common lynx 

 cowry, the former of which is variously spotted, while the 

 latter still retains distinct transverse dark and light bands. 

 Still more striking is the difference between the immature 

 and adult conditions of the lesser false Argus cowi-j, as 

 shown in Fig. 4, the latter exhibiting small white spots on 

 a dark ground, while the former is banded with dark and 

 light, without the slightest trace of spotting. It will be 

 observed that this species of cowry is of a long narrow 

 shape, and it would seem, for two reasons, probable that 

 that is the primitive form of cowries ; the short and broad 

 shape, as shown in Fig. 1, «, being a later modification. 

 One of the reasons in favour of this view is that almost all 

 cowries which retain the primitive banding in the adult 

 condition are of the long form. Among such may be 

 mentioned the little wasp cowry (Fig. 3, b), the mole cowry 

 (C. falpa), remarkable for its tawny back and dark brown 

 base, and one variety of the carnelian cowry (C. carncola), as 

 well as the orange-tipped cowry ( C. isabelhi). Again, in 

 the true Argus cowry (Fig. G), which develops peculiar 

 ringed spots in the adult condition, the primitive bands are 

 still more or less distinctly traceable at all ages. 



To exemplify the second reason for the same view, we 

 may take the serpent's-head cowry, of which the adult is 

 shown in Figure 1, a. Here we see the short round type in 

 its full development, the coloration being chocolate brown 

 above and below, with the central area of the back finely 

 spotted with white. If, however, we take a young indi- 

 vidual of this species, it will be noticed that the shape of 

 the shell is comparatively long and narrow, while the 

 colouring is in the form of bands. Many other instances 

 might be cited, but the foregoing are sufficient for my 

 present purpose. 



I may accordingly pass on to notice briefly some of 

 the more striking types of coloration presented by adult 

 cowries, and here I must deplore the circumstance that 

 editorial commands restrict the number of Illustrations to 

 my article.* Banded cowries have been already men- 



* I am inclebtetl for the photographs from which these illustrations 

 were taken to Jlr. N. M. Kichardson, of ilonte Video, near 

 Wevmouth. 



tioned, but it may be added that, from the intensity of the 

 colours, the wasp cowry (Figure 3, b) is not improbably 

 the culmination of this type. ( in the other hand, in the 

 flesh-coloured carnelian cowry, of which there is both a 

 long and a short form, the bands tend to become very in- 

 distinct : and it may be suggested that the short form is 

 not far removed from the ancestral type of the beautiful 

 orange cowry, which is one of the few uniformly coloured 

 species ; such uniformly coloured forms indicating, aa 

 already said, one line of specialization. 



Among the spotted cowries several types are noticeable. 

 Firstly, we have species in which the back of the shell is 

 simply spotted with black or brown, among them being the 

 tiger cowry (C ti(iris), the panther cowry (f. panthi rina) , 

 and the much smaller lynx cowry (i . lijnx). As all these 

 have a comparatively short and wide shell they indicate 

 an advanced type. Next, we have white-spotted cowries, 

 such as the false argus (C. cn-i-wi), the lesser false argus 

 (Fig. t), and the fallow-deer cowry (C. viteUus) ; and 

 as the two former are long-shaped, while the latter is 

 comparatively short, they seem to indicate a medium stage 

 of evolution. 



From the black- and brown-spotted types seem to have 

 originated another group represented by the map and nutmeg 

 cowries (C. mtiii/iu and ambica, Fig. ,5), in which the spots 

 are retained along the margins of the back of the shell, the 

 central area of which is more or less finely reticulated or 

 vermiculated, the map cowry taking its name from the width 

 and sinuosity of the line between the mantle lobes. In the 

 typical nutmeg cowry the reticulations are very nutmeg-like, 

 but in other specimens more or less distinct pale spots are 

 dotted all over the central area, till in the variety histrin 

 (Fig. 1, c] the spots are the dominant feature, being only 

 separated by thin lines, so as to form a kind of network, 

 or honeycomb arrangement. Perhaps the colander cowry 

 (Fig. 3, c) may be regarded as an offshoot of this type. 



But another modification may apparently also be traced 

 to the arabica-iiifijipa stock, the members of which are 

 intermediate between the long and the short types. As 

 already said, these cowries have the central area of the back 

 reticulated or white-spotted, and lighter than the black- 

 spotted margin. And from such a type the transition is 

 easy to the modification presented by the serpent's-head 

 cowry (Fig. 1, a), and the Sarinamtoad cowry, in which 

 the central area is white- or chestnut-spotted, while the 

 margin and much of the under surface is dark brown. The 

 great width and shortness of these cowries afford further 

 evidence of their high degree of modification. Obviously 

 the chestnut-bordered cowry (Fig. 1 , rf) is another member 

 of this group in which chestnut spots have been superadded 

 to the normal white-spotted central area. Apparently a 

 special development of this type may be recognized in the 

 white ring cowry (C. annuluK), the yellow ring from which 

 it takes its name marking the line of division between the 

 original spotted central area and the dark area. Finally, 

 from the ring cowry may easily be derived the money 

 cowry, in which the ring has all but disappeared, whUe the 

 marginal area has developed a series of rugosities, apparently 

 connected with the filaments on the margins of the mantle 

 lobes, which scarcely intrude on to the central area. 

 Whether these two white species have a habitat different 

 from that of their brethren is a subject well worth the 

 investigation ot those who have the opportunity. 



Omitting mention of certain other sub-types on account 

 of limitation of space, this part of the subject may be con- 

 cluded by brief reference to the true argus cowry (C argus, 

 Fig. 6),which, from its elongated form and the retention of 

 barring, is evidently an ancient type specially distinguished 

 by the ring-like form of the spots. 



