274 Dr. P. P. Carpenter on Pleistocene Fossils 
are first of all developed, and that fecundation is effected by the 
spermatia falling upon the base of the apothecium and fecun- 
dating the hymeneal corpuscles, which afterwards have the 
faculty of investing themselves with a membrane, and thus 
progenerate the asci and within them the spores. 
In the diclinous species, further investigations are needful to 
ascertain the mode of fecundation. 
On the above subject Dr.W. Nylander thus writes in the ‘Flora’ 
of Dec. 9, 1865, p.579 :—“ Notare liceat, spermatia, quee videre 
crediderunt clarissimi Garovaglio et Gibelli in supera parte cavi- 
tatis apotheciorum apud Verrucari vas, nulla talia sistere vera. 
Filamenta ostiolaria seepissime apice fragmenta tenella compres- 
sione secernere conspiciuntur, hocce autem longe distat ab ele- 
mentis spermogonicis (cf. Nyl. in Flora, 1864, p. 354, et ibidem 
p- 358 exemplum allatum paraphysium et filamentorum ostio- 
larium optime consociatorum in eodem perithecio) .” 
XXIX.—On the Pleistocene Fossils collected by Col. K. Jewett 
at Sta. Barbara (California) ; with Descriptions of new Species. 
By Puirre P. Carpenter, B.A., Ph.D. 
Tue study of the recent and tertiary mollusks of the west coast 
of America is peculiarly interesting and instructive, for the fol- 
lowing reasons. It is the largest unbroken line of coast in the 
world, extending from 60° N. to 55° S., without any material 
salience except the promontory of Lower California. Being 
flanked by an almost continuous series of mountain-ranges, the 
highest in the New World, it might reasonably be supposed that 
the coast-line had been separated from the Atlantic from remote 
ages. The almost entire dissimilarity of its faunas from those 
of the Pacific Islands, from which it is separated by an immense 
breadth of deep ocean from north to south, marks it out as con- 
taining the most isolated of all existing groups of species, both in | 
its tropical and its temperate regions. When we go back in time, 
we are struck by the entire absence of anything like the boreal 
drift, which has left its ice-scratchings and arctic shells over so 
large a portion of the remaining temperate regions of the northern 
hemisphere, and also by the very limited remains of what can 
fairly be assigned to the Eocene age. The great bulk of the 
land on the Pacific slope of North America (so far as it is not 
of voleanic origin) appears to have been deposited during the 
Miocene epoch. Here and there only are found beds whose 
fossils agree in the main with those now living in the neigh- 
bourig seas. To trace the correspondences and differences 
