No. 380.] REVIEWS OF RECENT LITERATURE. 589 
NEUROMERES. SoMITES. NERVES NERVES VISCERAL VISCERAL 
(DORSAL). (VENTRAL). CLEFTs. 
I mar I (olf.) lost 
II I oph. pr. V. III lost z 
Ill 2 Vv IV mouth I 
IV 3 (Vv)? (VI)? lost (1)? 
V 4 VII (VI)? I 2 
VI 5 IX (VI)? 3 
VII 6 X VI 3 4 
VIII 7 X 1 spinal? 4 5 
IX 8 1 spinal* -f spinal” 5 6 
Xx 9 2 spinal’ x spinal? 6 lost ® 
XI 3 spinal * lost® lost® 
Neal further concludes that there was originally a correspondence 
between neuromerism, mesomerism, and branchiomerism, and that 
a visceral arch has been lost in the region of the fourth neuromere. 
The segments VIII to XI have been added from the trunk region to 
the occipital region, the number varying in different vertebrates. 
Many details are given of the development of the neural anlagen 
nerves, somites, etc., and comparisons are made with Amphioxus, 
the results of which are summarized as follows : 
“In agreement with van Wijhe, I homologize the mouth of 
Amphioxus with the left half of the mouth of Craniota. The first 
pair of permanent visceral clefts in Amphioxus are exactly homolo- 
gous with the hyomandibular clefts of higher vertebrates. The eight 
visceral clefts possessed by Amphioxus at its ‘critical stage’ 
(Willey) are exactly homologous with the eight morphological clefts 
found in some Selachii and Cyclostomes.” 
Closely connected with the subject of this paper by Dr. Neal is a 
shorter but suggestive article’ by Mr. Cole, which, however, is based 
upon the anatomical rather than the embryological side of the prob- 
lem. The matter is so condensed as to admit of no satisfactory 
abstract, since it deals not with new investigations, but is rather a 
Summary of conclusions drawn from existing knowledge. 
1 Possibly represented by labial cartilages. 
? Theoretical relationships. 
3 From the first three roots of the embryonic PTPR 
* Fuses with dorsal ganglion of X. 
7 Reflections on the Cranial Nerves and Sense Organs of Fishes, by F. J. Cole. 
Trans. Liverpool Biol. Soc., vol. xii, 1898. 
