H. A. Baylis 
257 
IV. Oesophagus with a posterior glandular portion, or ventriculus, often 
bent so as to open into the intestine laterally. An intestinal caecum present. 
No oesophageal appendix. Examples: Ascaris decipiens, A. depressa, A. ensi- 
caudata, Porrocaecum crassum, Terranova antarctica, probably Ascaris semi- 
teres , A. serpentulus 1 . 
V. Oesophagus with a reduced posterior ventriculus, giving off a back- 
wardly-directed glandular appendix. An intestinal caecum also present. 
Examples: Ascaris aucta, A. microcephala, Contracaecum spiculiyerum, Kath- 
leena osculata , K. radiata , K. rodhaini, K. tricuspis. 
The subfamily Heterocheilinae, Railliet and Henry. 
We may next consider the classification outlined by Railliet and Henry 
(1912), to which reference has already been made. These authors divided the 
family Ascaridae into the following subfamilies: 
(1) Ascarinae, to include Ascaris L. and other genera with a simple 
alimentary canal. 
(2) Anisakinae, to include Anisakis Duj., 1845 (= Peritrachelius Dies., 
1851; = Conocephalus Dies., 1861) and perhaps Crossocephalus Railliet, 1909 
(= Pterocephalus v. Linst., 1899). 
(3) Heterocheilinae, to include provisionally all the forms with oeso¬ 
phageal or intestinal caeca. Heterocheilus Dies., 1839; Typhlophorus v. Linst., 
1906; Porrocaecum Railliet and Henry, 1912; Crossopliorus Hempr. and Ehbr., 
1828; Lecanocephalus Dies., 1839; Contracaecum Railliet and Henry, 1912. 
To these were subsequently added (1915) the genera Terranova and Kathleena 
of Leiper and Atkinson, 1914, and Paphidascaris Railliet and Henry, 1915. 
With the first subfamily it is not intended to deal at present. Of the 
forms included in the last two subfamilies, it is important to note the following 
features. 
Anisakis (type-species (?) “ Ascaris simplex Rud.” of Dujardin—type- 
specimens renamed A. dussumieri by van Beneden, 1870—? synonym, Peri¬ 
trachelius [ Conocephalus ] typicus (Dies., 1860); Host, Delphinus). The main 
character upon which Dujardin’s subgenus Anisakis was based was the 
presence of two spicules of unequal length in the male. The descriptions of 
A. dussumieri and of Ascaris [ Peritrachelius ] tyjoica show, however, that the 
oesophagus possesses a posterior ventriculus of different histological appear- 
ance from the anterior, muscular portion, and that oesophageal and intestinal 
caeca are absent. (See Stiles and Hassall (1899), where the anatomy and the 
complicated synonymy are fully dealt with.) 
Crossocephalus , as more recent researches (Gedoelst (1916); Baylis (1919, a)) 
1 The material available for the study of the last two forms did not permit of satisfactory 
examination. 
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