PROFESSOR E. P. WRIGHT ON THE TEREDIDÆ. 567 
the soft mud—this tube being added to, in all probability, according as the mud rises, 
and then arched over and covered in so as to serve as a perfect case, the Zeredo still pre- 
serving unmodified its shelly boring valves; while other very closely allied species live in 
timber, where the same old habit is kept up of having a shelly tube, even in some 
cases arched over, and oftentimes concamerated, and this tube often attaining almost 
the dimensions and solidity of the mud-loving form. 
Do not these facts seem to indicate that such forms as K. arenarius are the older forms, 
allied to the more typical mud-boring Mollusca through such genera as Gastrochæna, 
Clavagella, and Brechites, and that gradually, as the Teredines became wood-borers, 
they became somewhat altered, not only in their habits, but in their functions? The 
shelly tube, no longer a necessity, was more feebly, and then not at all, secreted; and 
except when the mollusk bored too near to the surface, there would be no occasion for 
any protection from soft mud and sand, and the tube would seldom if ever be covered in. 
I hope, through the kindness of Mr. Weir and of Mr. Mann, to receive specimens of 
the tubes, if any, secreted by Æ. ? mannii, and also recent specimens of Calobates tho- 
racites, from Singapore, so that I may be enabled to satisfy myself more completely on 
some of the points referred to in this paper. 
I hardly need here add that the circumstance of these two last-mentioned forms being 
found living in the timber of the same jetty does not at all imply that they necessarily 
belong to the same genus or species. It not unfrequently happens that several species 
of Teredines are found boring into one log of timber. ; À : 
I owe many thanks to Mr. H. Adams for his kindness, not only in lending me speci- 
mens of C. thoracites, but also for obtaining for me the specimens of K. mamm. 
Nav 2, . (Plate LXV. figs. 9-15.) i 
Le a aues freshwater Teredo from India. 
(Vide Trans. Linn. Soc. vol. xxiv. p. 451, plate xlvi) The RER AR: rn. ante 
at the time sufficient to justify me in making a new genus for its ie wen 
absence of the auricle in the valves, these being bilobed, and the peculiar io ud five 
bricated blades of the palettes. Since then (January 1864) I nis a tn thes 
additional specimens of this species ; and these characters RT, A diwely allied 
new species, however, now under consideration, while the peni are furnished 
to Nausitora than to any other of the genera of the Teredidæ, f j^ s reception, 1 prefer 
with well-developed auricles. Rather than make a new eee pists them from the 
to slightly modify the generic characters of the genus Nausiora, 
form of the siphonal palettes, rather than from the valves. 
The genus Nausitora was established for 
The characters of this new 
: eous, somew hat 
species may be briefly given as follows .—Valves small, ch anteriorly it is 
longer than broad. The * triangular area " is small, obtuse n those which are found 
Shining, the lines of sculpture having broader gee as the “triangular area,” 
9n the “ central portion." This latter is half as broad ag 
itudinal lines of 
i E t knob. The longitudina i 
and a little more than twice as long, ending 1n ? a inuation of those on the “tri- 
"ülpture on one half of this p Qeon Ae amp = = lines of sculpture gradually 
Angular area,” the transverse lines are better marked; 
