638 PROFESSOR E, RAY LANKESTER. 
the feet of the Nauplius or larva of Cirripedia and Copepoda ; 
(4) the digestive tract is homologous throughout with that of 
Crustacea, particularly the Decapoda, there being no urinary 
tubes, asin Tracheata; (5) the heart is on the Crustacean 
type as much as on the Tracheate type, and the internal 
reproductive crgans (ovaries and testes) open externally, at 
the base of and in the limbs, much as in Crustacea.” 
To this series of statements I would reply categorically— 
(1) the “nature of the branchie” is xo¢ such as is found in 
any Crustacean, but is only paralleled in the lamelligerous 
appendages of “Arachnida. Other animals have branchiz 
besides Crustacea. The mode of respiration is neither truly 
nor falsely Crustacean, but is simply ‘ branchial.’ 
(2) The cephalothorax of Limulus does noé resemble that 
of Apus, but differs from it as much as it does from any 
Arthropodous cephalothorax, as, for example, in the over- 
lapping of posterior segments by the free posterior margin 
of the carapace of Apus ; ; in the excavation of the carapace 
in Apus by the shell-glands ; in the widely different position 
of the first and second pair of appendages in relation to the 
cephalothoracic margin ; in the total difference of the eyes ; 
and, above all, in the totally different form, number, and 
arrangement of the gnathites. 
(3) The gnathopods have zo ‘‘ general resemblance to 
the feet of the Nauplius” which calls for remark. They 
have a general resemblance to the feet of any Arthropod, 
but less to the feet of the Nauplius than to many other varie- 
ties of Arthropod feet, owing to the fact that the former are 
biramose, non- -chelate, natatory, and feebly chitinized, which 
those of Limulus are not. 
(4) The digestive tract is homologous throughout, not only 
with that of Crustacea, but with that of all other Arthro- 
pods. How Dr. Packard can suppose that itis homologous, 
particularly with that of Decapoda, I am unable to compre- 
hend, unless he proposed to himself, when writing this pas- 
sage, to associate Limulus genealogically in a special branch 
with the Decapoda. Unless this is the case Dr. Packard 
makes use of the word ‘homologous’ with a meaning 
which is unusual and unknown to me. 
(5) That “ the heart is on the Crustacean type as much 
as or the Tracheate type” I will not dispute, for I do not 
feel sure that I know what Dr. Packard means, and he 
appears to take up a neutral attitude, in regard to the heart 
at any rate. I will, however, remark that, putting types 
aside, there is no heart of a Crustacean which so closely re- 
sembles the King Crab’s as does that of the Arachnid 
